1. Field of the Invention
The present invention relates generally to electrical connectors, and more specifically to devices that may be found in electrical circuitry connecting a pyrotechnic firing system to pyrotechnic projectiles.
2. Description of the Related Art
"Pyrotechnics" is the "science of fire." Almost everyone is familiar with fireworks shows created by exploding pyrotechnic devices. Fireworks displays have been created and enjoyed for centuries by millions of people. Over the years, the systems and methods for creating the displays have remained substantially unchanged.
Fireworks systems in the prior art are comprised essentially of two main components, namely a pyrotechnic projectile and a mortar for directing the pyrotechnic projectile into the air. The pyrotechnic projectile itself consists of two principal components, comprising an initial burst and a main burst. Black powder is one of the oldest pyrotechnic propulsion agents and is typically used as the initial burst and main burst component. The main burst also includes pellets of color composition known as "stars." Igniting the stars during detonation of the main burst provides the light and color of the fireworks display.
A pyrotechnic projectile has two fuses in the form of an initial fuse and a main fuse. The main fuse extends from the initial burst in the outer shell of the projectile to the main burst in the inner shell of the projectile. The initial fuse extends from the initial burst to the exterior of the outer shell. By igniting the initial fuse, the initial burst is exploded and propels the pyrotechnic projectile from the mortar into the air. Contemporaneously, the main fuse is lit because the end of the main fuse protrudes into the initial burst. The main fuse then takes a specific time to burn into and ignite the main burst.
A number of methods are known to ignite the initial burst. One such method is to apply a flame to a flammable cord leading to the initial fuse. While this method is simple, it may present safety hazards and is not suitable for more creative and comprehensive fireworks displays that require precise timing and sequencing of a series of fuse ignitions. For these more comprehensive shows, a firing control system, using electrical signals, is commonly employed. Electrical wires are used to connect the initial fuses of multiple pyrotechnic projectiles to the firing control system, which controls the firing sequence of the projectiles in accordance with the fireworks show requirements.
With today's more complex fireworks shows, it is imperative that the components connecting the firing control system and the pyrotechnic projectiles be durable, easy to use for multiple display applications, and easy to replace. Recently, theme parks and other entertainment venues have been providing fireworks displays that are associated with water shows. Often in these situations, the components making up the firing circuits are located in close proximity to water from being mounted on floating barges in a lagoon or lake. For this reason, it is desirable that such components be corrosion-resistant. One vital component of an electric firing circuit in a pyrotechnic display system is the connector that connects the wiring from the firing control system to the wiring of the initial fuses in the projectiles. Where the pyrotechnic system is exposed to water, it is not only important that the connecting device be durable, easy to use and corrosion-resistant, it should also provide a tight seal to prevent shorting of the electrical components in the firing control system caused by contact with water.
Connectors that have been found to be suitable for use with land-based fireworks displays include the Admiral "ADLOC AL2000" and the "Kingspin." While suited for such applications, these connectors have drawbacks when used near or on water. The ADLOC AL2000 does not provide a waterproof seal and allows water to enter the electronics of the firing control system. Leakage into the electronics causes numerous problems: fireworks can unexpectedly explode, causing a danger to personnel working on the systems or show; also, fireworks may fire out of sequence, all at once, or not at all, resulting in very poor quality displays. The ADLOC is also not very durable and cannot withstand the constant impacts associated with barge-based pyrotechnics shows.
The Kingspin is not easy to use. It requires the user to depress the head of the connector to a precise position that exposes an opening into which the end of the wire from a pyrotechnic projectile is inserted. Spring tension resists this pressure, and the user must hold the connector in the proper position until he or she is successful in passing the wire into the opening. This operation may require several tries and can be very time consuming. It is also known that inadvertent impacts during show preparation or operation from equipment or personnel on top of the connector may cause the opening to be exposed and the wiring to be disengaged.
An additional problem with both the Kingspin and the ADLOC AL2000 is that when one component of either connector wears out, gets corroded or otherwise becomes non-usable, the entire connector must be replaced.
From the foregoing description, it should be apparent that there is a need for an electrical connector for use with a pyrotechnic system that is durable and corrosion-resistant. It is also desirable to provide such a device that provides a watertight seal preventing the leakage of water into the firing control system. It is further desirable that such a device be able to withstand frequent contact by operators and equipment without allowing disengagement of wiring. It is yet further desirable to provide such a device that is easy to use in single applications as well as for multiple show applications. It is still further desirable to provide such a device where individual components may be replaced as required while being able to continue use of those components of the device that are still in usable condition. It is yet further desirable to provide such a device that can replace existing devices without requiring that any special modifications or accommodations be made to existing facilities. The present invention satisfies these needs and provides further related advantages.